Originally Posted by
jghilino
all i know about sub arc is its flat position welding and they use some type of sand as flux, other than that i have no idea
"Have you considered making a home made roto phase to run 3 phase equipment off of single phase." i have no idea but its worth looking into, this 220 volt equipiment is not what im used to using. All the welders we use at powerplants are 480 3 phase. I guess i could y 2 220volt buzz boxes together so i could run 300 amps off of 220 current as another option.
Since this eqiupment is wired 3 phase 220 volts you got half the battle beat as this is the voltage required to use the roto phase.
A roto phase is not a conveter, it merly adds the missing 3rd leg to your 3 phase equipment.
Easy to make, all you need is a 3 phase electric motor wired for 220 volts. Look on the manufactures tag for the voltages the motor will run on.
Ok the three phase motor does not have start windings, but it does require 3 live. For your roto phase your going to take two live wires from your electrical service connected to a switch. Use a washiing machine or similar 110 volt single phase motor to get the 3 phase turning over then switch on the 220 volts from your single phase mains.
Are you with me so far, now that the 3 phase is running under its own power no longer required the 110 volt electric motor, that empty 3rd leg that should have had t he 3rd leg from the 3 phase service is actually generating power. Yes sir this is the leg you need to run three phase equipment such as welders, lathe or milling machine. You name it you can run it.
You can build more complicated roto's that use capacitors to self start, I prefer the cheap way using the 110 volt electric motor.
For a more permanent situation over using belts and pulleys couple the two electric motors together using a love joy coupler, that 110 will just spin along with the roto while its powered up.
Get a 5 hp 3 phase for this project the scrap yards have plenty and sell by the pound.
If your running a lathe and the motor is running opposite to what the start switch indicates, just swap any pair of wire going to the lathe - bingo your motor now starts in the right direction.
I love 3 phase equipment when its sold on auction no one know how to deal with it, so it sell cheap.
Using any 3 phase electric motor up to 10 horse power, just feed two wires from your 220 volt single phase source and tap your 3rd leg off of that spare wire which now goes to the 3 phase equipment you want to power up.
Just remember to get that 3 phase motor turning first before giving her the juice.
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